High-pressure stages of multistage piston compressors are known, for example from GB-PS No. 1,487,311. In said known high-pressure piston compressor, it is no longer necessary to maintain an oil film between the piston and the working surface of the cylinder for the purpose of sealing and lubricating, i.e., to permanently lucricate with oil, as graphite is used for the working surface for said purpose, and self-lubricating plastic material is used for the actual sealing elements, such plastic material being suitable for this case of application. However, nothing has changed in the known and conventional design of the piston in the high-pressure stage, i.e., in order to obtain adequate tightness between the piston and the working surface of the cylinder, provision has to be made for a great number of piston rings in matching annular grooves on the piston. Aside from the manufacturing expenditure in that regard, the piston rings seated in the annular grooves of the piston must, of course, have a certain clearance with respect to said rings, and furthermore, measures are required to insure that the piston rings will always rest against the working surface of the cylinder. This is unavoidably connected with losses due to leaking, leakage and wear, and additionally with leakage losses resulting from such wear.